* Lufthansa jets to provide clues for probe on missing plane
* Captured data on temperatures, wind but not turbulence
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GENEVA, June 2 Two Lufthansa jets believed to have been in the same area half an hour before the missing Air France flight are to provide clues for the investigation, the World Meteorological Organisation (WMO) said.
The United Nations weather agency said on Tuesday it had preliminary information indicating the two aircraft recorded data on prevailing temperatures and winds. But they were not equipped to automatically transmit information on turbulence.
On Monday, a source with access to the data transmitted to WMO told Reuters in Paris that the two jets passed through turbulence before and after the plane without incident, leaving experts scrambling to assess the weather's role in the disaster.
Brazilian search planes spotted debris in the Atlantic Ocean on Tuesday that could be the wreckage of Air France flight 447 carrying 228 people that disappeared in a storm on Sunday night.
Herbert Puempel, chief of the WMO's aeronautical meteorology division, said that it was highly unlikely that lightning or bad weather caused the accident, noting all aircraft are equipped to fly in inclement weather, but they may have contributed.
"Two Lufthansa planes were somewhere in the vicinity of the Air France flight but we don't know the exact location of the accident, it is extremely difficult to say how close they were," Puempel told Reuters.
The two aircraft were believed to be going from South America to Europe, on Sunday night, in the same direction as the Air France flight from Rio to Paris.
"It is difficult to judge the value of the observation when you don't know how far away it was," he said. "But the observations will certainly be used by the investigating group."
More than 5,000 aircraft collect data under WMO's Aircraft Meteorological Data Relay Programme (AMDAR). The two Lufthansa jets participated in the system, but not the Air France flight, according to the Geneva-based agency.
The data supports weather forecasting, climate predictions, and early warning systems ahead of natural disasters.
Weather phenomena associated with thunderstorms are typically very localised and short-lived, Puempel said. If a plane reports turbulence, another one passing through the area even shortly afterwards is unlikely to experience it.
The source with access to the data, a specialist in aviation weather who declined to be identified, said on Monday that lightning appeared to be a "red herring". (Editing by Jonathan Lynn and Jon Hemming)